It is planned to continue work on the properties of under methylated DNA as a template for in vitro DNA synthesis. This will include research on the DNA polymerases and ligases necessary for this synthesis and studies of the physical state of the template DNA. The characterization of possible methylation mutants in E. coli B will be continued. This will include: mapping of these mutants, transduction to suitable K 12 strains, and determination of the mutational defect if possible.